FIG. 6 is a vertical sectional side view illustrating the conventional vehicular fuel supply apparatus disclosed in Japanese Utility Model Publication No. 1-37178, for example. In the Figure, 1 is a fuel tank storing fuel 2 therein, 1a is a bottom wall of the fuel tank 1, 1b is a bottom wall opening disposed in the bottom wall 1a of the fuel tank 1. 3 is a set plate attached to the bottom wall opening 1b via a packing 4 in an oil-tight manner. Provided on the inside surface 3a of the set plate 3 are a sub-tank 5 inserted into the interior of the fuel tank 1 and an in-tank type fuel pump 7 mounted to the inside bottom surface 5a of the sub-tank 5, and a suction filter 8 is mounted to a suction port 7a of the fuel pump 7. The sub-tank 5 is provided in order to prevent the fuel 2 from being not supplied from the fuel pump 7 to the engine (not shown) even when the vehicle body tilts in the state that the fuel 2 within the fuel tank 1 is reduced.
The discharge port 7b of the fuel pump 7 has a main tube 10 connected thereto by a rubber hose 9, the tube 10 being bent downwardly to oil-tightly pass through the set plate 3 and being connected by a joint 14 to a delivery pipe 16 extending to the engine (not shown). Further, a power supply line 11 having a connector 12 attached to the exterior of the fuel tank 1 is passed through the set plate 3 in an oil-tight manner and connected to a power supply terminal 13 of the fuel pump 7.
Disposed at the downstream side of the delivery pipe 16 are a fuel filter 17 located outside of the fuel filter 1 for filtering the dusts within the fuel 2, an injector 18 for injecting fuel into each cylinder of the engine and a pressure regulator 19 for regulating the pressure of the fuel injected from the injector 18 to be constant. The return pipe 20 is disposed for returning a portion of the fuel 2 as an excess fuel from the pressure regulator 19 to the fuel tank 1 and the an end portion 20a on the fuel tank 1 side extends through the set plate 3 to open within the fuel tank 1.
Then, the operation of the conventional vehicular fuel supply apparatus will now be described.
By applying a voltage from the power supply terminal 13 through the connector 12 and the power supply line 11 to drive the fuel pump 7, the fuel 2 in the fuel tank 1 is sucked from the suction filter 8, pressurized in the fuel pump 7 and supplied through the main tube 10 to the delivery pipe 16 extending toward the engine. Thereafter, the fuel 2 is filtered in the fuel filter 17 and injected into each cylinder of the engine from the injector 18. In order that the pressure regulator 19 regulates the fuel pressure to be constant, a portion of the fuel 2 is returned to the fuel tank 1 as an excess fuel from the pressure regulator 19 through the return pipe 20.
In the above-described vehicular fuel supply apparatus, mounting parts (not shown) for attaching the fuel filter 17 and the pressure regulator 19 disposed at the outside of the fuel tank 1 is necessary, so that the vehicle body weight is increased and the steps for assembling the vehicle body assembly is increased, resulting in a cost increase.
Also, since the sub-tank 5 is cup-shaped that is open at the lop end 5b, the fuel 2 within the sub-tank 5 can flow over the top end 5b of the sub-tank 5 to out of the sub-tank 5. Therefore, a problem has been raised in that the function as a sub-tank, which prevents the fuel from not being supplied to the engine by the fuel pump 7 when the fuel 2 within the fuel tank 1 is decreased, is deteriorated.
Further, another problem has been presented in that, when the set plate 3 is to be assembled into the fuel tank 1, the power supply line 11 for energizing the fuel pump 7 is damaged by the edge of the opening 1b of the fuel tank 1, thereby damaging the insulation on the surface of the power supply line 11.
This invention has been made to solve the above-discussed problems and has as its object the provision of a vehicular fuel supply apparatus in which the vehicle weight and the cost are not increased due to the attaching parts for the fuel filter and the pressure regulator.
Another object is to provide a vehicular fuel supply apparatus in which the function of the sub-tank cannot be damaged even at the time of an abrupt starting and abrupt braking of the vehicle when the fuel is decreased.
Further object is to provide a vehicular fuel supply apparatus that is free from the damages to the insulation on the power supply line surface at the time of assembly.